Africa has seen economic booms before—from oil, diamonds, and more—but hardly any have benefited ordinary Africans. This one might be different.

As of March 2004, the telecommunications sector was the fastest-growing employer in Nigeria. It directly employed 5000 people, indirectly employed 400 000, attracted more than US $4 billion in investment the year before and contributed about 3 percent to the gross domestic product—and this was when Nigeria's cellphone companies boasted only 4 million subscribers. There are more than 19 million today.

While carriers can provide jobs to qualified engineers and administrators, indirect employment can help spread the wealth even to those who don't have the benefit of education or the right connections. Again, without reliable data to consult, we must rely on our own observations to document the trickle-down effect wireless carriers are having on African economies. One indicator of the telecommunications industry's deep penetration into the everyday economy is the ubiquitous wireless-phone kiosk, where customers can rent mobile phones by the minute.

Cheap to set up and lucrative to operate, kiosks often provide a family's sole income stream. Owners initially invest about $100 to build a small shack and to buy a handset and charger, an expense of $40 to $60. The SIM card and activation could cost another $10 to $20. In Kenya, mobile-service entrepreneurs often forgo the shack and instead carry handsets on lanyards around their necks, finding customers as they stroll around marketplaces.

The average cost of a 3-minute mobile-to-mobile phone call in sub-Saharan Africa is 57 cents. Overseas calls made from a wireless phone are an even greater bargain, which has let African businesses connect to foreign partners at much cheaper international calling rates than those charged on landlines. For example, the average cost of a call from Cameroon to the United States is 50 cents per minute using a mobile phone, while the same call on a landline phone is $6 per minute. That's because most landline international phone calls from Cameroon are routed through France, which charges switching fees. Wireless telephony helps Africans bypass the European tollgate and bounce calls to satellites for long-distance service.

Most kiosk owners we surveyed in Kenya charge about 25 cents per minute for a local call and about 50 cents for an international one. Kiosk owners and strolling vendors alike earn as much as $400 per month, much more than what many college graduates earn at Kenyan corporations.

The sale of prepaid cards themselves has become big business. In Cameroon, Ethiopia, Kenya, and Uganda, most convenience stores do brisk business selling prepaid phone cards. Informal evidence suggests that these cards generate thousands of dollars per year in extra revenue. Card sellers who do not own convenience stores stand by the roadside or trawl through traffic jams to ply their trade [see photo, "Curbside Service"]. Card vendors make more money than government secretaries and elementary school teachers do; many of them own one or more mobile phones themselves.

In fact, ambitious kiosk owners—and many business people—often need to own multiple handsets to place calls on a country's separate networks. That's a direct result of the failure of telecom regulators to mandate that networks interoperate. In most sub-Saharan countries, wireless companies do not allow rivals access to their networks. (This is also true of countries in other turbulent and developing regions; see "Iraq Goes Wireless," in the March 2006 issue of IEEE Spectrum.) MTN and Vodacom customers can't place calls to one another. In the short term, totally separate networks translate into more handsets for people who can afford them and more customers for certain carriers. In the long term, the industry risks increasing customer dissatisfaction as the novelty of ready access to telecommunications wears off and customers begin to demand better quality of service.

For both good and bad, the age of affordable cellphonesis as much a social phenomenon as an economic revolution. Equipped with mobile phones, poll-watching citizens can instantly report ballot fraud. Spouses cheat on each other by secretly and silently arranging dates via text messages. And criminals go to extreme lengths to get their hands on coveted handsets, sometimes even impersonating taxi drivers and picking up only passengers carrying handsets they want to steal.

The sub-Saharan region is notorious for its history of undemocratic practices. Its checkered past is littered with stories of nominally democratic elections that have been hijacked by incumbent presidents. But this situation is changing with increased access to wireless technologies, news media, and the Internet, which have combined to educate Africans about democratic practices and human rights.

A good example is Senegal's 2000 presidential election, when citizens armed with radios and cellphones helped to prevent incumbent president Abdou Diouf from rigging the elections. During the balloting, city-dwelling Senegalese walked around with handheld radios and mobile phones. Radio stations sent reporters to hundreds of individual voting bureaus. Within minutes of the local officials' announcing the result, the reporters got on their mobile phones and broadcast it. Given the situation, it was difficult for the authorities to massage the result without the electorate's knowing all about it. Diouf, who had been president since 1981 and had come in a clear second to president-elect Abdoulaye Wade, peaceably abdicated power.

Election monitoring isn't just good for democracy; it can be good for business, too. In Kenya, Safaricom gives paying customers election results via text messages. It launched its Get-It 411 short message services in 2002 to provide subscribers with local and international news, sports scores, horoscopes, movie listings, inspirational quotes, and election updates, each of which can be sent to the user for a fee of 7 shillings (about 10 U.S. cents) per message.

While some Africans wield their cellphones to protect their fledgling democracies, others thumb the keypad for that most prurient of purposes—the booty call\0xFEFF. Mobile telephony provides a new, convenient way to carry on affairs without risking a spouse's overhearing plans for an illicit rendezvous. Lovers often communicate with text messages or "beeping"—one party dials another's number and then hangs up. Beep buddies usually work out a code between themselves. One ring could mean, "I am here," two rings, "Call me now." In most of Asia, Europe, and Africa, where the calling party pays only upon connection, beeping is a cheap way to send a signal.

That's not to say that the carriers are losing out when facilitating love connections. On the contrary, an affluent, philandering husband may be great for business. His social network depends on him: the more ladies he romances, the bigger his network grows, and the more people he pays to connect. Say John has three phones, one for his wife and family on one carrier, one for his business on another, and one for his mistress on yet another. He will almost certainly buy seven phone cards: three for himself, one for his wife, one for his parents, one for his wife's parents, and one for his mistress. His mistress might ask him to buy a phone card for her mother and her sister. One paying user, but nine times the business.

While it is impossible to precisely quantify the impact such social networks might have on the phenomenal growth wireless carriers currently enjoy, the consequence of one man's losing his livelihood could be that nine fewer phone cards are purchased during a particular time. Scale up those numbers in the event of an economic downturn, and a country's cellphone boom could quickly go bust. Looking only at the number of subscribers that carriers trumpet in their press releases doesn't tell the whole story. As we've seen in our travels, there's a serious need for more comprehensive, quantitative studies of both the economics and the social dynamics that underpin Africa's wireless sector.

Africa no longer has a problem with the lack of telecommunications infrastructure, because most of the region's inhabitants are now, or soon will be, covered by mobile signals. In the long run, however, some countries might have trouble sustaining these new services, partly because of a lack of investment strategies and financial management skills at the street level and partly because of capital drain, a hidden consequence of the privatization policies that have fostered Africa's wireless boom.

We view this boom and the jobs it brings with cautious optimism. On the one hand, cellphones have triggered a substantial increase in complementary service jobs, such as vendors who sell prepaid cards, cellphone covers, handsets, and headsets. It is still the case, however, that most vendors live hand-to-mouth, not surprising in these traditionally agrarian societies. Neither kiosk owners nor street vendors are saving for future business investments that might eventually help them move beyond subsistence. We recommend that African governments provide basic financial management training programs for vendors, especially kiosk owners, who need help to look beyond their immediate financial gains to a sustainable future.

The issue of sustainability extends to businesses as well. More than 80 percent of cellphones purchased in sub-Saharan African countries are for personal use, not business. In fact, fewer than 10 percent of the region's businesses provide employees with cellphones for day-to-day business-related transactions. If this trend continues without aggressive endeavors to leverage wireless telecommunications to promote other economic sectors, the new economic ladder erected by the wireless industry will rest on very shaky ground indeed.

Finally, there is the issue of capital flow. The privatization process in most sub-Saharan countries aims to attract both local and foreign investors. It is often the case, however, that privatization hinges almost entirely on foreign investments, especially from Europe and the United States. Foreign investors bring resources that most local investors do not, such as the initial capital for infrastructure, and they tend to win the majority of wireless licenses. Although this could be a good strategy in the short run, it remains to be seen whether this approach promotes sustainable development within the region, considering that most of the returns on such investments accrue to foreign shareholders and are not plowed back into Africa—a typical form of neocolonialism. African regulators need to develop strategies to promote local investments in the wireless arena, as well as in other telecommunications sectors. They could benefit tremendously from more research in this area.

That said, foreign investment is key to raising the incomes and living standards of Africans. There is still a long list of items that African nations and the world at large need to address—including electric power, housing, clean drinking water, public health, and education. But at least now we can check off telecommunications. Wireless carriers have connected individuals and businesses to the rest of the world and, most important, to each other. It's a giant step on the long road to development.